Machines and facilities for handling objects and articles as well as for processing products usually comprise numerous components, modules, and facility parts that require maintenance and/or calibration at regular or irregular intervals. Such manual interventions can lead to the risk of collisions with rotating or moving parts of the facility or machine. Thus, individual facility parts commonly comprise a machine intended for the according production process, with said machine being enclosed by a housing that is supposed to provide protection against personnel intervening in the machine's working area. The housing can also be designed in such a way that the machine is additionally protected from external influences such as humidity, dust or the like. This allows ensuring sterile conditions within the facility part in question, if required.
In bottle handling and processing facilities as well as, for instance, in labeling equipment, persons are usually protected from safety hazards by means of separating protection devices. If, for purposes of maintenance, cleaning or repair works, or for troubleshooting, it is required for the protection device to be movable or removable, the protection device must be safeguarded by means of a safety switch. According to the existing hazard potential, the switch has to comprise a so-called tumbler and a locking mechanism. For the implementation of currently valid safety regulations according to the European Norm standards EN ISO 14121 and 13849, the safety switches have to be equipped with two circuits.
Patent DE 10 2007 047 733 A1 discloses a bottle handling facility with a safety device that comprises a first, accessible safety region, which is limited by a first protection, intended for a first machine with at least one drive allocated to the said first safety region. The safety device of the bottle handling facility further comprises a second, accessible safety region, which is limited by a second protection that is immediately adjacent to the first protection, intended for a second machine with at least one further drive allocated to the said second safety region. The bottles are conveyed from the first to the second machine by transport equipment that operates across the safety regions and is provided with its own drive. Furthermore, the safety device comprises a cut-off device, so that, on entering any of the two safety regions, the power is cut off for the at least one machine drive and the drive of the transport equipment allocated to the respective safety region.
Patent DE 20 2004 020 863 U1 furthermore discloses a device for securing a working area that is at least partly endangered by a machine, with said working area comprising an endangered sub-area and a sub-area that is less dangerous or not at all endangered. Two security systems are provided, whereby one of the security systems pertains to a high security category and can be established, for instance, by a light curtain or a light barrier arrangement. The second security system pertains to a lower security category and can be established, for instance, by a laser scanner or an infrared sensor. A signal is generated with the use of a signal triggering stage for the event that the security system pertaining to the high security category detects an object that has entered into the endangered working area, whereby at the same time and by means of the second security system pertaining to the lower security category it is ascertained that there is no object in the less or non-endangered sub-area. An example given in the said patent to illustrate such a machine is a robot that moves within the endangered sub-area, thus changing the sub-area with its movements.